In GIS, the term 'isoline' refers to what?

The term 'isoline' in GIS indeed refers to a line that connects points of equal value for a specific variable, such as elevation, temperature, or rainfall. This type of line is fundamentally important in various fields, including meteorology, geography, and environmental science, as it allows for the visualization of gradients and variations across a geographic area.

Isolines can help interpret patterns and relationships in spatial data, thereby aiding in decision-making and analysis. For example, a contour line representing equal elevation on a topographic map allows users to visualize terrain features, while isotherms would show lines of equal temperature in a climatic study. The essence of isolines lies in their ability to make complex data more comprehensible through graphical representation, consistently relating to how the value of the variable being represented changes across space.

In contrast, the other descriptions do not accurately represent the function of isolines. A line representing a single category of data could be a boundary or a categorical variable line rather than an isoline. Decorative lines do not convey quantitative information and thus do not fit the definition of an isoline. High traffic areas may be represented in a different manner, such as using heat maps, rather than as isolines. Therefore, the correct definition highlights the